Oscar winner Brie Larson has shown off her comedy skills by pretending to be the desperate fourth sister of sibling rockers Haim in a new Funny or Die video.

The Room star dons a long brown wig to portray Frime Haim for the sketch, in which she tells 'sisters' Danielle, Este, and Alana she's ready to join the family group.

"I have really exciting news," she tells the sceptical musicians. "I'm ready to be in the band!"

As Alana shoots down her hopes, insisting, "It's not gonna happen," the actress, in character, quips, "Well, why the frick not? Why can't it be four sisters? I mean, The Beatles made it work!"

Ignoring Este's attempts to point out the fact the Fab Four stars were not related, Brie, as Frime, continues to plead with the trio.

"I'm just tired of you guys being ashamed of me. I am your sister!" she says, before mispronouncing the girls' last name. "No one even knows who Frime Haim is!"

Brie even picks up a guitar to try and show off her musical talents, telling the band, "I'll have you know, I've been working on my own tunes in the studio... I wrote this song."

She proceeds to strum on the guitar and sing a reworked version of The Beatles' Hey Jude, changing the lyrics to: "Hey dudes/Don't make me mad/I'm the fourth Haim/I'll make it better."

"That's Hey Jude," notes Alana, prompting Brie's Frime to respond, "Well, what can I say? Those brothers know what up (sic)!"

The hilarious sketch draws to a close with a surprise appearance from singer Carnie Wilson, who plays the girls' mom and also expresses her desire to join Haim.

"There's already four girls in this band, mom," replies Brie, as she cuddles up to her weary siblings. "Get out!"

The Funny or Die clip appears to be an effort to promote Haim's new album, Something to Tell You, which hits retailers on 7 July (17).